To explore the structural determinants of different functional properties of proteins: 1. Investigation of the topology of the primary and secondary active site domains of serine esterases using active site-specific reagents 2. Investigation of the effect of natural and artificial cross-links on the in vivo stability of proteins. 3. Exploration of the role of the carbohydrate units in glycoproteins as determinants for compartmentalization and in vivo half-life.